This project involves both independent and collaborative work in chemical carcinogenesis where mass spectrometry, nuclear magnetic resonance and other chemical spectral methods can be applied to determine the structure and to confirm the identity of organic molecules. The research is focused in the following areas: (1) Spectral characteristics and chemical reactivity pattern of carcinogenic aromatic amines, amides and their N-hydroxylated and N-acetoxylated derivatives provide useful information, which may serve to explain their biological mode of action. The 2-aminofluorene derivatives are examined in detail. (2) Synthesis of stable isotope labeled open chain dialkylnitrosamines and subsequent mass spectral studies allowed a thorough rationalization of the gas phase cation radical behavior of this class of carcinogens. It was found that the significant hydroxyl radical lost in the mass spectra of nitrosamines does not involve hydrogens on carbon-1, -2 or from more distant sites but in all probability originates from carbon-3. There is now good analogy to this finding in radical oxidation reactions in solution and in the microsomal metabolism of nitrosamines. (3) Chemical and mass spectrometric studies on various labeled analogs of several derivatives of diols, triols and tetrols of polycyclic aromatic hydrocarbons revealed selective chemical reactivities and diagnostic mass spectral patterns. (4) An active area of interest is the development of methods for derivatization and analysis of carcinogens and other bioactive materials. (a) Thus, fast atom bombardment mass spectra on guanethidine N-oxide and electron impact spectra on its hexafluoroacetylacetone derivative provided full structural information for this enzyme substrate for flavin containing monooxygenase. (b) Improved ionization conditions were developed for analysis of nonvolatile biological materials with 4-cyanopyridinium hydrochloride. (c) Plans are initiated to adapt and improve the existing technology of sequencing polypeptides using fast atom bombardment ionization mass spectrometry and to apply it to structure studies of cell modulating factors.